The pause and stop callbacks duplicate the sequence that updates a sink buffer and finishes the current AUX output transaction. Move the common sequence into etm_event_update_buffer() for a single implementation.
The helper first verifies that perf handle is active. It updates the buffer when PERF_EF_UPDATE is requested and otherwise ends the transaction without data. The pause callback can then start a new perf handle for resuming trace.
Assisted-by: Codex:gpt-6 Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-etm-perf.c | 89 ++++++++++-------------- 1 file changed, 36 insertions(+), 53 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index a45f69f39f175f3044322b25fe5413fb97154496..13d865ca86f1161b2e21174f096473c4829afc8c 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -637,6 +637,38 @@ static void etm_event_start(struct perf_event *event, int flags) return; }
+static void etm_event_update_buffer(struct perf_output_handle *handle, + struct etm_event_data *event_data, + struct coresight_device *sink, + int mode) +{ + unsigned long size; + + /* + * Make sure the handle is still valid, as the sink may close it from + * the IRQ handler. E.g., the sink driver may fail to restart the + * handle during interrupt handling due to insufficient buffer space. + * The sink driver must serialize update_buffer() with IRQ handling, + * so this should return either a valid handle with a valid size + * (which may be 0), or no handle at all. + */ + if (!perf_get_aux(handle)) + return; + + if (!sink_ops(sink)->update_buffer) + goto out; + + if (mode & PERF_EF_UPDATE) { + size = sink_ops(sink)->update_buffer(sink, handle, + event_data->snk_config); + perf_aux_output_end(handle, size); + return; + } + +out: + perf_aux_output_end(handle, 0); +} + static void etm_event_pause(struct coresight_path *path, struct perf_event *event, struct etm_ctxt *ctxt) @@ -644,7 +676,6 @@ static void etm_event_pause(struct coresight_path *path, struct perf_output_handle *handle = &ctxt->handle; struct coresight_device *source, *sink; struct etm_event_data *event_data; - unsigned long size;
if (!path) return; @@ -669,27 +700,16 @@ static void etm_event_pause(struct coresight_path *path, if (WARN_ON_ONCE(handle->event != event)) return;
- if (!sink_ops(sink)->update_buffer) - return; - event_data = READ_ONCE(ctxt->event_data); - size = sink_ops(sink)->update_buffer(sink, handle, - event_data->snk_config); - if (READ_ONCE(handle->event)) { - if (!size) - return; + etm_event_update_buffer(handle, event_data, sink, PERF_EF_UPDATE);
- perf_aux_output_end(handle, size); - perf_aux_output_begin(handle, event); - } else { - WARN_ON_ONCE(size); - } + /* Prepare the handle for resuming trace */ + perf_aux_output_begin(handle, event); }
static void etm_event_stop(struct perf_event *event, int mode) { int cpu = smp_processor_id(); - unsigned long size; struct coresight_device *source, *sink; struct etm_ctxt *ctxt = this_cpu_ptr(&etm_ctxt); struct perf_output_handle *handle = &ctxt->handle; @@ -742,45 +762,8 @@ static void etm_event_stop(struct perf_event *event, int mode) /* tell the core */ event->hw.state = PERF_HES_STOPPED;
- /* - * If the handle is not bound to an event anymore - * (e.g, the sink driver was unable to restart the - * handle due to lack of buffer space), we don't - * have to do anything here. - */ - if (!handle->event) - goto out; - - if (mode & PERF_EF_UPDATE) { - if (WARN_ON_ONCE(handle->event != event)) - goto out; - - /* update trace information */ - if (!sink_ops(sink)->update_buffer) - goto out; + etm_event_update_buffer(handle, event_data, sink, mode);
- size = sink_ops(sink)->update_buffer(sink, handle, - event_data->snk_config); - /* - * Make sure the handle is still valid as the - * sink could have closed it from an IRQ. - * The sink driver must handle the race with - * update_buffer() and IRQ. Thus either we - * should get a valid handle and valid size - * (which may be 0). - * - * But we should never get a non-zero size with - * an invalid handle. - */ - if (READ_ONCE(handle->event)) - perf_aux_output_end(handle, size); - else - WARN_ON(size); - } else { - perf_aux_output_end(handle, 0); - } - -out: /* Disabling the path make its elements available to other sessions */ coresight_disable_path(path); }